20:10-12 The Israelites are here directed about the nations on whom they made war. Let this show God's grace in dealing with sinners. He proclaims peace, and beseeches them to be reconciled. Let it also show us our duty in dealing with our brethren. Whoever are for war, we must be for peace. Of the cities given to Israel, none of their inhabitants must be left. Since it could not be expected that they should be cured of their idolatry, they would hurt Israel. These regulations are not the rules of our conduct, but Christ's law of love. The horrors of war must fill the feeling heart with anguish upon every recollection; and are proofs of the wickedness of man, the power of Satan, and the just vengeance of God, who thus scourges a guilty world. But how dreadful their case who are engaged in unequal conflict with their Maker, who will not submit to render him the easy tribute of worship and praise! Certain ruin awaits them. Let neither the number nor the power of the enemies of our souls dismay us; nor let even our own weakness cause us to tremble or to faint. The Lord will save us; but in this war let none engage whose hearts are fond of the world, or afraid of the cross and the conflict. Care is here taken that in besieging cities the fruit-trees should not be destroyed. God is a better friend to man than he is to himself; and God's law consults our interests and comforts; while our own appetites and passions, which we indulge, are enemies to our welfare. Many of the Divine precepts restrain us from destroying that which is for our life and food. The Jews understand this as forbidding all wilful waste upon any account whatsoever. Every creature of God is good; as nothing is to be refused, so nothing is to be abused. We may live to want what we carelessly waste.

Verses 16-20. - This was for cities at a distance; it was to be otherwise with the cities of the Canaanites. To them no offer of peaceful submission was to be made, and when the city was taken, all the inhabitants without reserve were to be destroyed. This was in accordance with God's command to Israel (Exodus 23:31-33; Exodus 34:11-16; Deuteronomy 7:1-3), and as a precaution against the risk of the people being seduced into idolatry by the heathen should they be allowed to remain in the land. But whilst engaged in besieging a town, they were not to destroy the fruit trees that were outside the walls; but trees that were not for food they might cut down and use in their operations against the city.

But of the cities of those people, which the Lord thy God doth give thee for an inheritance,.... The cities of the seven nations, six of which are mentioned by name in the next verse:

thou shalt save alive nothing that breatheth; the reason of this severity was because of their wickedness, the capital crimes and gross abominations they were guilty of, and for which they deserved to die; and on account whereof they were reserved to this destruction, when the measure of their iniquities was full, such as idolatry, incest, witchcraft, soothsaying, necromancy, &c. see Leviticus 18:3.

Laws of Warfare…15"Thus you shall do to all the cities that are very far from you, which are not of the cities of these nations nearby. 16"Only in the cities of these peoples that the LORD your God is giving you as an inheritance, you shall not leave alive anything that breathes.17"But you shall utterly destroy them, the Hittite and the Amorite, the Canaanite and the Perizzite, the Hivite and the Jebusite, as the LORD your God has commanded you,…

Cross References

Exodus 23:31"I will establish your borders from the Red Sea to the Mediterranean Sea, and from the desert to the Euphrates River. I will give into your hands the people who live in the land, and you will drive them out before you.

Numbers 21:2Then Israel made this vow to the LORD: "If you will deliver these people into our hands, we will totally destroy their cities."

Numbers 21:3The LORD listened to Israel's plea and gave the Canaanites over to them. They completely destroyed them and their towns; so the place was named Hormah.

Numbers 31:17Now kill all the boys. And kill every woman who has slept with a man,

Deuteronomy 7:1When the LORD your God brings you into the land you are entering to possess and drives out before you many nations--the Hittites, Girgashites, Amorites, Canaanites, Perizzites, Hivites and Jebusites, seven nations larger and stronger than you--

Deuteronomy 20:15This is how you are to treat all the cities that are at a distance from you and do not belong to the nations nearby.

Joshua 6:21They devoted the city to the LORD and destroyed with the sword every living thing in it--men and women, young and old, cattle, sheep and donkeys.

Joshua 6:24Then they burned the whole city and everything in it, but they put the silver and gold and the articles of bronze and iron into the treasury of the LORD's house.

Joshua 8:8When you have taken the city, set it on fire. Do what the LORD has commanded. See to it; you have my orders."

Joshua 8:25Twelve thousand men and women fell that day--all the people of Ai.

Joshua 10:20So Joshua and the Israelites defeated them completely, but a few survivors managed to reach their fortified cities.

Joshua 10:28That day Joshua took Makkedah. He put the city and its king to the sword and totally destroyed everyone in it. He left no survivors. And he did to the king of Makkedah as he had done to the king of Jericho.

Joshua 10:40So Joshua subdued the whole region, including the hill country, the Negev, the western foothills and the mountain slopes, together with all their kings. He left no survivors. He totally destroyed all who breathed, just as the LORD, the God of Israel, had commanded.

Joshua 11:11Everyone in it they put to the sword. They totally destroyed them, not sparing anyone that breathed, and he burned Hazor itself.

Joshua 11:12Joshua took all these royal cities and their kings and put them to the sword. He totally destroyed them, as Moses the servant of the LORD had commanded.

Joshua 11:14The Israelites carried off for themselves all the plunder and livestock of these cities, but all the people they put to the sword until they completely destroyed them, not sparing anyone that breathed.

1 Samuel 15:3Now go, attack the Amalekites and totally destroy all that belongs to them. Do not spare them; put to death men and women, children and infants, cattle and sheep, camels and donkeys.'"

Treasury of Scripture

But of the cities of these people, which the LORD your God does give you for an inheritance, you shall save alive nothing that breathes: